Dark matter has eluded scientists for years. We're pretty sure that it exists (whatever it is), because we've seen gravitational evidence for it. But since it's invisible, we're not at all sure what we're looking for. However, scientists believe that dark matter has certain features that can be observed, and hope to discover those with MIT’s DarkLight lab project.
The theory of dark matter is that it accounts for a huge portion of total mass in the Universe. Scientists began studying it after discovering discrepancies in the masses of things like galaxies, where there was a significant amount of mass that was unaccounted for. This mass is believed to be dark matter, but we have no proof of that. A variety of ideas have been proposed concerning it, but the MIT scientists hope to narrow down their research to one leading theory that believes dark matter is actually a sort of large photon. DarkLight will be looking for that photon.
The MIT team developed their own particle accelerator for the project. The machine will put out a small beam of electrons at a high power. The beam will detect dark matter by looking at what it decays into. DarkLight is also capable of much more, though. It can also be used to study what happens inside stars to determine where the Universe’s oxygen supply comes from. Needless to say, if all goes well, physics will never be the same.
Don’t expect results any time soon, though. DarkLight isn’t scheduled to be ready to begin its search for two more years. And it may take several years after that to study the data it collects. Until then, it'll be back to poking at boring old exotic particles like the Higgs boson.